Inbound Marketing University

I'm working on a social media strategy for a corporate & commercial law firm, and am deliberating whether to create one profile page, then off that vertical channels by topic / interest / community, or should I create a separate profile page for each, e.g. Firm + Recruitment + Alumni - 3 profile pages all linked to the same firm? The profile page I refer to inlcudes creating one for each of the major SM sites, and smaller more niche environments.